Abstract

Gettier problems or cases are named in honor of the American philosopher Edmund Gettier, who discovered them in 1963. They function as challenges to the philosophical tradition of defining knowledge of a proposition as justified true belief in that proposition. The problems are actual or possible situations in which someone has a belief that is both true and well supported by evidence, yet which — according to almost all epistemologists — fails to be knowledge. Gettier’s original article had a dramatic impact, as epistemologists began trying to ascertain afresh what knowledge is, with almost all agreeing that Gettier had refuted the traditional definition of knowledge. They have made many attempts to repair or replace that traditional definition of knowledge, resulting in several new conceptions of knowledge and of justificatory support. In this respect, Gettier sparked a period of pronounced epistemological energy and innovation — all with a single two-and-a-half page article. There is no consensus, however, that any one of the attempts to solve the Gettier challenge has succeeded in fully defining what it is to have knowledge of a truth or fact. So, the force of that challenge continues to be felt in various ways, and to various extents, within epistemology. Sometimes, the challenge is ignored in frustration at the existence of so many possibly failed efforts to solve it. Often, the assumption is made that somehow it can — and will, one of these days — be solved. Usually, it is agreed to show something about knowledge, even if not all epistemologists concur as to exactly what it shows